Rocker arms dislodging on certain engines is a common problem and is usually misdiagnosed.
So, A customer comes in and complains of a poor running engine. After diagnosing it you find engine misfire codes.
And, To narrow down the issue you do a compression test or cylinder leak down test. Now, You have isolated a specific cylinder and confirmed cylinder leakage by the valves.
So, You remove a valve cover only to find rocker arms dislodging from their position. Your first thought may be to just reinstall the rocker and see what happens. You do this and it seems to run fine. You believe the problem is solved, or is it?
Well this is a lot more common than you think. It may be ok for two weeks or two months, but it will be back. If you are lucky enough to not have a total failure the next time it comes back; you will probably remove the cylinder head and send it to a machine shop for inspection.
When they call you back they are probably going to tell you that a valve seat has come loose. What happened was it moved down in it’s bore, it created a gap at the valve tip. As a result, This allowed the rocker to fall out of its location.
Possible Causes Of Rocker Arms Dislodging – Along With Valve Seats Falling Out
There are a number of reasons for rocker arm dislodging and some are more common than others. Some things to consider are:
Something causing the valve to stick in the open position allowing a gap for the rocker to shoot out:
- Poor fuel
- Debris in oil
- Bent valve
- Valve seat coming loose and dislodging
A valve seat coming loose, is probably the worst case and is very common in certain engines:
- 1991-1996 Ford 1.9
- 1997-2000 Ford 2.0
- 2002-2007 Chrysler 3.7
- 1999-2009 Chrysler 4.7
- 2003-2009 Chrysler 5.7
After removing the cylinder head this is what you might find. The seat is spinning and moving in and out of its bore. Usually the valve spring pressure just pulls it back in. Therefore, At some point it will come all the way out and cause major damage.
This is repairable at most machine shops but they might recommend replacing all the valve seats as a precaution. For some reason the Intake Valve Seat is more of a problem than the exhaust. Consequently, Caused by insufficient crush between the valve seat and the machined hole to accept it.
This Is What You Might See After Removing The Cylinder Head
Some of the earlier 1.9 and 2.0 Ford engines had what they called; powdered metal inserts that would actually break or just explode. When a valve seat comes out of it’s counterbore, it shatters or explodes into tiny pieces from impact. As a result, those pieces from the valve seat may get lodged in the intake or exhaust manifolds.
NOTE: Not cleaning out all that debris will cause a second failure as it gets sucked in a second time.
Other Known Causes Of Rocker Arms Dislodging May Include:
- Broken valve springs ( causing ticking or misfires )
- Engine Overheating
- Stuck Valves
- Old Fuel Issues
So, The result of letting this go to long is; you could drop a valve seat and possibly a valve; causing complete destruction of the engine. That is why analyzing what caused the problem before you try to fix it is so important. Broken or burned valves as well as worn or loose guides; cracked or loose seats and similar valve train damage; is often the end result of a chain reaction of events.
One problem leads to another and eventually a valve failure. So, Replacing parts without understanding what made them fail is no fix at all. Finally, Cooling problems in the engine itself can lead to valve sticking if the operating temperature gets too high.
Some Things That Can Make Your Engine Run Hot Are:
- Low coolant
- Defective thermostat
- Weak water pump
- Radiator obstruction
- Defective cooling fan or fan switch
This, in turn, makes the valve stems swell which may cause them to gall or stick in their guides. Usually, If there is not enough clearance. As a result, If the valve sticks open, it can burn or be destroyed if it smacks the piston. Hence, This can all be the result of rocker arms dislodging.
So, No one said it would be a straightforward fix. But, Diagnosing why the original failure happened is key to keep it from happening again.
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